Cursor control devices (CCD) used in aircraft such as onboard the Boeing 787 utilize a capacitive touch sensitive human interface device. Existing CCDs exhibit erratic behavior and even inoperability under certain circumstances. Variation in skin moisture and operating environment, contaminates, and even user body size can have an effect on how the touch sensor reacts. If the user has very dry skin, the CCD may not react to a touch at all.
A very high impedance in the return path of the touch sensor results in a very small signal amplitude; sometimes only a few millivolts. Variability in the signal amplitude due to environmental and user specific factors result in an unreliable system.
Consequently, it would be advantageous if an apparatus existed that is suitable for removing variability in touch sensor signals due to environmental and user specific factors.